2002 mer sable 3.0 u eng code 303 misfire

Question

2002 mer sable 3.0 u eng code 303 and p316 new injecter new plug new plug wire

Answer 1

Hi there,

First, and it may seem silly, make sure you are actually working on cylinder #3. If this is good, then the coil itself could be the issue, so replace it. If the coil doesn't resolve the problem, check for vacuum leaks at the intake on #3 and check the engine compression on cylinder #3.